These safety calculators implement standardized methods for ergonomic and acoustic risk assessment in occupational settings. The Lifting Index (LI) is based on the NIOSH equation (Waters et al., 1994): LI = Actual Load / Recommended Weight Limit, with the RWL derived from 6 multipliers (posture, distance, frequency, coupling, asymmetry, vertical distance). Logarithmic sound level summation is required for occupational noise exposure assessment per OSHA 29 CFR 1910.95 and ISO 9612.
Note: Advisory domain: results support risk assessment but do not replace a formal Job Hazard Analysis (JHA) or workplace safety evaluation by a qualified occupational health and safety professional.
LI = Actual Load / Recommended Weight Limit (RWL). RWL = LC × HM × VM × DM × FM × AM × CM. Where LC = 23 kg (51 lb) load constant, and multipliers HM (horizontal), VM (vertical), DM (distance), FM (frequency), AM (asymmetry), CM (coupling) are ≤ 1. LI < 1 = acceptable risk; 1 ≤ LI < 3 = increased risk; LI ≥ 3 = high risk.
Contact pressure
p = F / A [N/m² = Pa]. F is the force applied perpendicular to the surface [N], A is the contact area [m²]. Relevant for assessing localized pressure risk on body surfaces and for structural bearing surface design.
Sound level summation
L_total = 10 × log₁₀(Σ 10^(Lᵢ/10)) [dB]. Sound levels in dB do not add arithmetically. Two identical sources at 80 dB produce 83 dB (not 160 dB). Required for calculating equivalent exposure level L_Aeq.
OSHA noise exposure limits
OSHA PEL: 90 dBA TWA (8-hour). Action level: 85 dBA TWA. NIOSH REL: 85 dBA TWA (8-hour). Per OSHA 29 CFR 1910.95, a hearing conservation program is required at the action level.
Manual material handling
Governed by ISO 11228-1 and OSHA guidelines. The indicative attention threshold for manual lifting is 23 kg (51 lb) under ideal conditions per the NIOSH equation.